Double-base propellant containing a ureide and a resorcylate

ABSTRACT

A double-base propellant of nitrocellulose and nitroglycerin which contains lead resorcylate for an improved exhaust, comparably higher burning rate and higher operating pressure.

United States Patent Lavitt DOUBLE-BASE PROPELLANT [75] Inventor: Joseph W. Lavitt, Succasunna, NJ.

[73] Assignee: The United States of America as represented by the Secretary of the Army, Washington, DC.

[22] Filed: June 7, 1967 [21] Appl. No.: 645,565

[52] U.S. Cl 149/98, 149/95, 149/92, 149/102 511 int. Cl C06b 5/04 [58] Field of Search 149/95, 97, 98, 92, 102

[56] References Cited UNITED STATES PATENTS 3,032,972 5/1962 Preckel 149/98 X Primary Examiner-Stephen J. Lechert, Jr. Attorney, Agent, or Firm-Robert P. Gibson; Nathan Edelberg; Edward F. Costigan [57] ABSTRACT A double-base propellant of nitrocellulose and nitroglycerin which contains lead resorcylate for an improved exhaust, comparably higher burning rate and higher operating pressure.

18 Claims, No Drawings DOUBLE-BASE PROPELLANT CONTAINING A UREIDE AND A RESORCYLATE This invention relates to smokeless double-base propellants containing nitrocellulose and nitroglycerin.

My patent application for Improved Nitrocellulose Base Propellants, Ser. No. 394,633, filed 4 Sept. 1964, relates to propellants having reduced smoke and moisture contents in their exhaust. A limitation of the propellants covered by the above basic application exist in the low burning rates and relatively low operating pressure obtained. However, some of the propulsion systems in use today require that the propellant produce a pressure of at least 1,000 pounds per square inch and a burning rate of at least 0.25 inches per second in order to operate properly. These latter requirements are not met by the propellants described in the above cited application.

It is therefore an object of this invention to provide a smokeless double-base propellant containing nitrocellulose and nitroglycerin having a relatively greater burning rate and producing a relatively higher operating pressure than that previously obtained by conventional propellants for use in propulsion systems requiring the same.

Other objects and many attendant advantages of this invention will be readily appreciated as the same become better understood by reference to the following detailed description.

It has now been discovered that if a lead salt of a re sorcylate is incorporated in the compositions disclosed in the above cited basic application, propellants may be produced having the exhaust properties, the burning rates, and operating pressures desired for special propulsion systems in use today. More specifically, ifa lead salt of a resorcylate is added to the compositions of the basic disclosure in an amount between 0.5 and 10.0%, the propellant thereby produced will have a smokeless exhaust, a burning rate of over 0.3 inches per second and an ideal operating pressure between 1,000 and 2,000 pounds per square inch. The lead resorcylate compounds which may be utilized to this advantage include lead alpha-resorcylate, lead beta-resorcylate, and lead gamma-resorcylate.

The basic compositions to which the lead resorcylate material may be incorporated to advantage include double-base propellants containing nitrocellulose and nitroglycerin. The basic compositions above described preferably include the following range of ingredients in specified amounts, on a weight basis, as follows, viz:

l. About 40 to 60% of nitrocellulose having a nitrogen content between about to 14.2%,

2. About to 34% of a nitrate ester of a polyhydroxy alcohol, preferably glycerol trinitrate,

3. About 5 to of an acetate ester of a polyhydroxy alcohol, preferably glycerol triacetate,

4. About 0.5 to 10% of monoalkali salt of a ureide, preferably monosodium barbiturate or sodium barbitol,

5. About 0.5 to 5.0% of a stabilizer such as ethyl centralite or 2-nitrodiphenylamine, and

6. Nitrogen bearing coolants such as oxamide may be added in amounts up to about 25% to obtain required flame temperature and ballistic properties.

The above composition may be manufactured by any ofthe processes available such as the solventless water slurry processing or the plastisol process, although somewhat better mechanical properties and ballistics are usually obtained when the solventless water slurry process is employed.

The following examples illustrate the manner of producing the composition including the manner of incorporating the lead resorcylate ingredient in the compositron.

EXAMPLE NO. I

A 30 lb. mix of an improved double-base propellant. hereinafter designated SMU-l 18, was manufactured by the solventless water slurry process which involved adding 14.49 lbs. or nitrocellulose containing about 12.6% nitrogen to 144.9 lbs. of water at F in a 55 gallon mix can equipped with an air driven mixer. The suspension was mixed for 10 minutes after which 8.01 lbs. of nitroglycerin were added. The mixture was again mixed for 10 minutes and a mixture containing 0.96 lbs. of lead beta-resorcylate and 0.30 lbs. of ethyl centralite in 7.23 lbs. of triacetin was added. The suspension was mixed again for 30 minutes after which it was poured into a suitable cotton duck bag. The water was then removed by centrifuging the bag in a suitable wringer to form a paste which was screened through a inch by 4 inch mesh screen and dried until the moisture content was 842%. The paste was then blended. 0.30 lbs. of sodium barbiturate being added to the paste during the blending. The paste was then rolled on differential speed rolls at 210F with a roll gap of 0.025 inch 1 0.005 inch at roller speeds of 22.5 and 15 rpm to obtain differential speed sheets. These sheets were then rolled on even speed rolls to form even speed sheets at i 10F at a roll speed of 1 1 rpm and roll gap of 0.035 inch i 0.005 inch.

EXAMPLE NO. II

A 1,700 lb. mix of an improved double base porpellant, hereinafter designated SM U-119, was manufactured by the solventless water slurry process which involved adding 821.] lbs. of nitrocellulose containing about 12.6% nitrogen to 9,853 lbs. of water at 120F. The suspension was mixed for 10 minutes after which 476 lbs. of nitroglycerin were added. The suspension was again mixed for ten minutes after which a premixed suspension of 17.0 lbs. of ethyl centralite and 54.4 lbs. of lead beta-resorcylate was added. The slurry was mixed for 30 minutes after which the excess water was removed by centrifuging in a wringer to form a paste which was screened through a A inch by A inch mesh screen and dried until the moisture content was 81 2%. The paste was then blended, 17.0 lbs. of sodium barbiturate being added to the paste during the blending. The paste was then rolled on differential speed rolls at 210F with a roll gap of 0.025 inch 1 0.005 inch at roller speeds of 22.5 and 15 rpm to obtain differential speed sheets. These sheets were then rolled on even speed rolls to form even speed sheets at 140i10F at a roll speed of 1 1 rpm and a roll gap of 0.035 inch i 0.005 inch.

Sheets produced by the methods described above in Exmaple I and Example 11 were prepared and tested for burning rate in the following manner. Strands, 7X%X/s inches, were cut from the sheets and ignited by a hot wire in the closed bomb of a conventional strand buming apparatus at specified temperatures and pressures. The time required for the ignited strand to burn a specified length is used to calculate the strand burning rate of the propellant. The burning rates obtained 3 4 were set forth in the table below and compared to the to advantage in the specialized propulsion systems in conventional burning rates of the compositions deuse today. scribed in the application which has been heretofore Further, propellant compositions, processed, in cited- 7 7 1 cordance with the procedures set forth in Examples I A and II, were then rolled into inch carpet rolls and ex- TABLE I truded in a 15 inch press through a die approximately 4 inches in diameter. Thereafter, several 2 inch test BURNING RATES motor grains were fabricated from these extrusions.

CON VENTlONAL COMPOSlTlONS The motor grains had the following dimensions, viz: (a) SMU-lOI SMU-I02 SMU-l l8 SMU-l 19 10 a length of 7.25 inches, (b) an outside diameter of 1.75

LOW i inches, and (c) an inside diameter of 0.6 inches. When pmsurei the machined grains were tired in standard 2 inch 400 0.158' 0.133 0.233 0.224 I rocket test motors, the attenuation of a beam of light 600 0158 08156 0174 0263 aust ases was measured and com ared to 800 0.078 0.168 0.302 0.292 5 by l exh p 900 0.086 0.168 0,323 similar data which had been obtained for a conven- 1000 0087 (H66 0337 0-304 tional propellant at ambient temperature. This data is 1100 0.095 0.162 0.331 1200 (M01 0.154 0340 0309 QMQE1QW1 22.2 2 i288 gig), in view of the data given above, it is quite evident 1800 0.142 0.178 0.303 0.234 20 that the propellant produced in accordance with this 2000 0.159 0.193 0.279 0.230 AmbiemTemp WP 70,: WP invention gives r1se to exhaust products having less pressure* smoke than conventional smokeless propellants. This 400 0.162 0.158 0.248 0.270 was confirmed by visual observation of the firings on a 288 3 closed circuit television screen and motion picture 900 0.118 0.181 0.385 2 5 films of the static firing which shows that the propellant 88 8-33 8-53 into which lead resorcylate is incorporated produces a 1200 0.151 0:181 0: cleaner exhaust than conventional smokeless propel- 0170 0-389 0-305 lants. Further, the pressure produced by the present 1600 0.180 0.208 0.357 0.292 l 8 h 1800 0306 0328 0284 propellants have idea operating pressures wit in t e 2000 0.204 0.230 0.298 0.301 range desired for the propulsion systems in use today. High Temp. 160F [00F 145F 165F "i Pmmrct This invention retains the synergistic effects taught in the above cited application while tailoring the burning 9,01) 55 0:199 :3 5 I rate and ideal operating presence of the propellant 'to suit the conventional and special equipment in use to-' H00 1 5 0:408 day. This is basically accomplished by incorporating 1588 0.18; 0.218 0.405 0.347 the lead salt of a resorcylate into a smokeless nitrocel- 0.20 0.223 0.395 0.334 1600 0226 0154 M50 0337 lulose double base propellant already containing the 1800 0.257 0.265 0.336 0.382 sodium salt of a ureide. 2000 0.260 0.276 0.327 0.394 l 40 Obviously, there are many modifications and varia- Tli''f flflilififif w.. tions which are possible in view of the above teachings. A comparison of the data, set forth in Table l, illus- It is therefore to be understood that these modifications trates that the conventional smokeless double-base and variations are to be included within the scope of propellants compositions into which the lead resorcythe appended claims. late is incorporated are useful as propellants at entirely I claim: different temperatures and pressures. Further, burning 1. In a smokeless double-base propellant containing rates. which were heretofore unobtainable with the nitrocellulose and nitroglycerin, the improvement conconventional compositions available, are now achieved sisting of the incorporation in said propellant of the sowith compositions having lead resorcylate as an ingredium salt of a ureide and a lead resorcylate to produce dient and therefore such compositions may be utilized the synergistic effects of cleaner exhaust, a burning rate TABLE II Conventional Propellant Propellant SMU-l18 SMU-ll9 Calculated Flame Temp,

1 2523 I 2540 Heat of Explosion cal/gm 700 704 Static Firing Data Pressure, psi 710 i268 1048 Mass rate of discharge lb/sec 0.340 0.795 0.792 Light Attenuation, /2 3.7 2.81 3.18 Specific Attenuation* 10.9 3.53 4.02

Light attenuation divided by mass rule of discharge.

of over about 0.25 inches per second, and an operating pressure of over about 1000 pounds per square inch.

2. The composition of claim 1 wherein said lead resorcylate is lead alpha-resorcylate.

3. The composition of claim 1 wherein said lead resorcylate is lead beta-resorcylate.

4. The composition of claim 1 wherein said lead resorcylate is lead gamma-resoreylate.

5. The composition of claim 1 wherein said lead resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.

6; The composition of claim 1 wherein said lead resorcylate is present in an amount of about 3.2 percent by weight.

7. The composition of claim 1 which contains sodium barbiturate and lead beta-resorcylate.

8. The composition of claim 1 which contains sodium barbitol and lead beta-resorcylate.

9. The composition of claim 2 wherein said lead alpha-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.

10. The composition of claim 2 wherein said lead alpba-resorcylate is present in an amount of about 3.2 percent by weight.

ll. The composition of claim 3 wherein said lead beta-resorcylate is present in-an amount between about 0.5 and 10.0 percent by weight.

12. The composition of claim 3 wherein said lead beta-resorcylate is present in an amount of about 3.2 percent by weight.

13. The composition of claim 4 wherein said lead gamma-resorcylate is present in an amount between about 0.5 and l0.0 percent by weight.

14. The composition of claim 4 wherein said lead gamma-resorcylate is present in an amount ofabout 3.2 percent by weight.

15. The composition of claim 7 wherein said lead beta-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.

16. The composition of claim 7 wherein said lead beta-resorcylate is present in an amount of about 3.2 percent by weight.

17. The composition of claim. 8 wherein said lead beta-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.

18. The composition of claim 8 wherein said lead beta-resorcylate is present in an amount of about 3.2 

1. IN A SMOKELESS DOUBLE-BASE PROPELLANT CONTAINING NITROCELLULOSE AND NITROGLYCERIN, THE IMPROVEMENT CONSISTING OF THE INCORPORATION IN SAID PROPELLANT OF THE SODIUM SALT OF A UREIDE AND A LEAD RECORCYLATE TO PRODUCE THE SYNERGISTIC EFFECTS OF CLEANER EXHAUST, A BURNING RATE OF OVER ABOUT 0.25 INCHES PER SECOND, AND AN OPERATING PRESSURE OF OVER ABOUT 1000 POUNDS PER SQUARE INCH.
 2. The composition of claim 1 wherein said lead resorcylate is lead alpha-resorcylate.
 3. The composition of claim 1 wherein said lead resorcylate is lead beta-resorcylate.
 4. The composition of claim 1 wherein said lead resorcylate is lead gamma-resorcylate.
 5. The composition of claim 1 wherein said lead resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.
 6. The composition of claim 1 wherein said lead resorcylate is present in an amount of about 3.2 percent by weight.
 7. The composition of claim 1 which contains sodium barbiturate and lead beta-resorcylate.
 8. The composition of claim 1 which contains sodium barbitol and lead beta-resorcylate.
 9. The composition of claim 2 wherein said lead alpha-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.
 10. The composition of claim 2 wherein said lead alpha-resorcylate is present in an amount of about 3.2 percent by weight.
 11. The composition of claim 3 wherein said lead beta-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.
 12. The composition of claim 3 wherein said lead beta-resorcylate is present in an amount of about 3.2 percent by weight.
 13. The composition of claim 4 wherein said lead gamma-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.
 14. The composition of claim 4 wherein said lead gamma-resorcylate is present in an amount of about 3.2 percent by weight.
 15. The composition of claim 7 wherein said lead beta-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.
 16. The composition of claim 7 wherein said lead beta-resorcylate is present in an amount of about 3.2 percent by weight.
 17. The composition of claim 8 wherein said lead beta-resorcylate is present in an amount between about 0.5 and 10.0 percent by weight.
 18. The composition of claim 8 wherein said lead beta-resorcylate is present in an amount of about 3.2 percent by weight. 